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certspotter/ct/x509/x509.go

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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package x509 parses X.509-encoded keys and certificates.
//
// START CT CHANGES
// This is a fork of the go library crypto/x509 package, it's more relaxed
// about certificates that it'll accept, and exports the TBSCertificate
// structure.
// END CT CHANGES
package x509
import (
"bytes"
"crypto"
"crypto/dsa"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rsa"
"crypto/sha1"
// START CT CHANGES
"src.agwa.name/ctwatch/ct/asn1"
"src.agwa.name/ctwatch/ct/x509/pkix"
// END CT CHANGES
"encoding/pem"
"errors"
// START CT CHANGES
"fmt"
// END CT CHANGES
"io"
"math/big"
"net"
"time"
)
// pkixPublicKey reflects a PKIX public key structure. See SubjectPublicKeyInfo
// in RFC 3280.
type pkixPublicKey struct {
Algo pkix.AlgorithmIdentifier
BitString asn1.BitString
}
// ParsePKIXPublicKey parses a DER encoded public key. These values are
// typically found in PEM blocks with "BEGIN PUBLIC KEY".
func ParsePKIXPublicKey(derBytes []byte) (pub interface{}, err error) {
var pki publicKeyInfo
if _, err = asn1.Unmarshal(derBytes, &pki); err != nil {
return
}
algo := getPublicKeyAlgorithmFromOID(pki.Algorithm.Algorithm)
if algo == UnknownPublicKeyAlgorithm {
return nil, errors.New("x509: unknown public key algorithm")
}
return parsePublicKey(algo, &pki)
}
func marshalPublicKey(pub interface{}) (publicKeyBytes []byte, publicKeyAlgorithm pkix.AlgorithmIdentifier, err error) {
switch pub := pub.(type) {
case *rsa.PublicKey:
publicKeyBytes, err = asn1.Marshal(rsaPublicKey{
N: pub.N,
E: pub.E,
})
publicKeyAlgorithm.Algorithm = oidPublicKeyRSA
// This is a NULL parameters value which is technically
// superfluous, but most other code includes it and, by
// doing this, we match their public key hashes.
publicKeyAlgorithm.Parameters = asn1.RawValue{
Tag: 5,
}
case *ecdsa.PublicKey:
publicKeyBytes = elliptic.Marshal(pub.Curve, pub.X, pub.Y)
oid, ok := oidFromNamedCurve(pub.Curve)
if !ok {
return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: unsupported elliptic curve")
}
publicKeyAlgorithm.Algorithm = oidPublicKeyECDSA
var paramBytes []byte
paramBytes, err = asn1.Marshal(oid)
if err != nil {
return
}
publicKeyAlgorithm.Parameters.FullBytes = paramBytes
default:
return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: only RSA and ECDSA public keys supported")
}
return publicKeyBytes, publicKeyAlgorithm, nil
}
// MarshalPKIXPublicKey serialises a public key to DER-encoded PKIX format.
func MarshalPKIXPublicKey(pub interface{}) ([]byte, error) {
var publicKeyBytes []byte
var publicKeyAlgorithm pkix.AlgorithmIdentifier
var err error
if publicKeyBytes, publicKeyAlgorithm, err = marshalPublicKey(pub); err != nil {
return nil, err
}
pkix := pkixPublicKey{
Algo: publicKeyAlgorithm,
BitString: asn1.BitString{
Bytes: publicKeyBytes,
BitLength: 8 * len(publicKeyBytes),
},
}
ret, _ := asn1.Marshal(pkix)
return ret, nil
}
// These structures reflect the ASN.1 structure of X.509 certificates.:
type certificate struct {
Raw asn1.RawContent
TBSCertificate tbsCertificate
SignatureAlgorithm pkix.AlgorithmIdentifier
SignatureValue asn1.BitString
}
type tbsCertificate struct {
Raw asn1.RawContent
Version int `asn1:"optional,explicit,default:1,tag:0"`
SerialNumber *big.Int
SignatureAlgorithm pkix.AlgorithmIdentifier
Issuer asn1.RawValue
Validity validity
Subject asn1.RawValue
PublicKey publicKeyInfo
UniqueId asn1.BitString `asn1:"optional,tag:1"`
SubjectUniqueId asn1.BitString `asn1:"optional,tag:2"`
Extensions []pkix.Extension `asn1:"optional,explicit,tag:3"`
}
type dsaAlgorithmParameters struct {
P, Q, G *big.Int
}
type dsaSignature struct {
R, S *big.Int
}
type ecdsaSignature dsaSignature
type validity struct {
NotBefore, NotAfter time.Time
}
type publicKeyInfo struct {
Raw asn1.RawContent
Algorithm pkix.AlgorithmIdentifier
PublicKey asn1.BitString
}
// RFC 5280, 4.2.1.1
type authKeyId struct {
Id []byte `asn1:"optional,tag:0"`
}
type SignatureAlgorithm int
const (
UnknownSignatureAlgorithm SignatureAlgorithm = iota
MD2WithRSA
MD5WithRSA
SHA1WithRSA
SHA256WithRSA
SHA384WithRSA
SHA512WithRSA
DSAWithSHA1
DSAWithSHA256
ECDSAWithSHA1
ECDSAWithSHA256
ECDSAWithSHA384
ECDSAWithSHA512
)
type PublicKeyAlgorithm int
const (
UnknownPublicKeyAlgorithm PublicKeyAlgorithm = iota
RSA
DSA
ECDSA
)
// OIDs for signature algorithms
//
// pkcs-1 OBJECT IDENTIFIER ::= {
// iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) 1 }
//
//
// RFC 3279 2.2.1 RSA Signature Algorithms
//
// md2WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 2 }
//
// md5WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 4 }
//
// sha-1WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 5 }
//
// dsaWithSha1 OBJECT IDENTIFIER ::= {
// iso(1) member-body(2) us(840) x9-57(10040) x9cm(4) 3 }
//
// RFC 3279 2.2.3 ECDSA Signature Algorithm
//
// ecdsa-with-SHA1 OBJECT IDENTIFIER ::= {
// iso(1) member-body(2) us(840) ansi-x962(10045)
// signatures(4) ecdsa-with-SHA1(1)}
//
//
// RFC 4055 5 PKCS #1 Version 1.5
//
// sha256WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 11 }
//
// sha384WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 12 }
//
// sha512WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 13 }
//
//
// RFC 5758 3.1 DSA Signature Algorithms
//
// dsaWithSha256 OBJECT IDENTIFIER ::= {
// joint-iso-ccitt(2) country(16) us(840) organization(1) gov(101)
// csor(3) algorithms(4) id-dsa-with-sha2(3) 2}
//
// RFC 5758 3.2 ECDSA Signature Algorithm
//
// ecdsa-with-SHA256 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
// us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 2 }
//
// ecdsa-with-SHA384 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
// us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 3 }
//
// ecdsa-with-SHA512 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
// us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 4 }
var (
oidSignatureMD2WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 2}
oidSignatureMD5WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 4}
oidSignatureSHA1WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 5}
oidSignatureSHA256WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 11}
oidSignatureSHA384WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 12}
oidSignatureSHA512WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 13}
oidSignatureDSAWithSHA1 = asn1.ObjectIdentifier{1, 2, 840, 10040, 4, 3}
oidSignatureDSAWithSHA256 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 4, 3, 2}
oidSignatureECDSAWithSHA1 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 1}
oidSignatureECDSAWithSHA256 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 2}
oidSignatureECDSAWithSHA384 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 3}
oidSignatureECDSAWithSHA512 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 4}
)
func getSignatureAlgorithmFromOID(oid asn1.ObjectIdentifier) SignatureAlgorithm {
switch {
case oid.Equal(oidSignatureMD2WithRSA):
return MD2WithRSA
case oid.Equal(oidSignatureMD5WithRSA):
return MD5WithRSA
case oid.Equal(oidSignatureSHA1WithRSA):
return SHA1WithRSA
case oid.Equal(oidSignatureSHA256WithRSA):
return SHA256WithRSA
case oid.Equal(oidSignatureSHA384WithRSA):
return SHA384WithRSA
case oid.Equal(oidSignatureSHA512WithRSA):
return SHA512WithRSA
case oid.Equal(oidSignatureDSAWithSHA1):
return DSAWithSHA1
case oid.Equal(oidSignatureDSAWithSHA256):
return DSAWithSHA256
case oid.Equal(oidSignatureECDSAWithSHA1):
return ECDSAWithSHA1
case oid.Equal(oidSignatureECDSAWithSHA256):
return ECDSAWithSHA256
case oid.Equal(oidSignatureECDSAWithSHA384):
return ECDSAWithSHA384
case oid.Equal(oidSignatureECDSAWithSHA512):
return ECDSAWithSHA512
}
return UnknownSignatureAlgorithm
}
// RFC 3279, 2.3 Public Key Algorithms
//
// pkcs-1 OBJECT IDENTIFIER ::== { iso(1) member-body(2) us(840)
// rsadsi(113549) pkcs(1) 1 }
//
// rsaEncryption OBJECT IDENTIFIER ::== { pkcs1-1 1 }
//
// id-dsa OBJECT IDENTIFIER ::== { iso(1) member-body(2) us(840)
// x9-57(10040) x9cm(4) 1 }
//
// RFC 5480, 2.1.1 Unrestricted Algorithm Identifier and Parameters
//
// id-ecPublicKey OBJECT IDENTIFIER ::= {
// iso(1) member-body(2) us(840) ansi-X9-62(10045) keyType(2) 1 }
var (
oidPublicKeyRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1}
oidPublicKeyDSA = asn1.ObjectIdentifier{1, 2, 840, 10040, 4, 1}
oidPublicKeyECDSA = asn1.ObjectIdentifier{1, 2, 840, 10045, 2, 1}
)
func getPublicKeyAlgorithmFromOID(oid asn1.ObjectIdentifier) PublicKeyAlgorithm {
switch {
case oid.Equal(oidPublicKeyRSA):
return RSA
case oid.Equal(oidPublicKeyDSA):
return DSA
case oid.Equal(oidPublicKeyECDSA):
return ECDSA
}
return UnknownPublicKeyAlgorithm
}
// RFC 5480, 2.1.1.1. Named Curve
//
// secp224r1 OBJECT IDENTIFIER ::= {
// iso(1) identified-organization(3) certicom(132) curve(0) 33 }
//
// secp256r1 OBJECT IDENTIFIER ::= {
// iso(1) member-body(2) us(840) ansi-X9-62(10045) curves(3)
// prime(1) 7 }
//
// secp384r1 OBJECT IDENTIFIER ::= {
// iso(1) identified-organization(3) certicom(132) curve(0) 34 }
//
// secp521r1 OBJECT IDENTIFIER ::= {
// iso(1) identified-organization(3) certicom(132) curve(0) 35 }
//
// NB: secp256r1 is equivalent to prime256v1
var (
oidNamedCurveP224 = asn1.ObjectIdentifier{1, 3, 132, 0, 33}
oidNamedCurveP256 = asn1.ObjectIdentifier{1, 2, 840, 10045, 3, 1, 7}
oidNamedCurveP384 = asn1.ObjectIdentifier{1, 3, 132, 0, 34}
oidNamedCurveP521 = asn1.ObjectIdentifier{1, 3, 132, 0, 35}
)
func namedCurveFromOID(oid asn1.ObjectIdentifier) elliptic.Curve {
switch {
case oid.Equal(oidNamedCurveP224):
return elliptic.P224()
case oid.Equal(oidNamedCurveP256):
return elliptic.P256()
case oid.Equal(oidNamedCurveP384):
return elliptic.P384()
case oid.Equal(oidNamedCurveP521):
return elliptic.P521()
}
return nil
}
func oidFromNamedCurve(curve elliptic.Curve) (asn1.ObjectIdentifier, bool) {
switch curve {
case elliptic.P224():
return oidNamedCurveP224, true
case elliptic.P256():
return oidNamedCurveP256, true
case elliptic.P384():
return oidNamedCurveP384, true
case elliptic.P521():
return oidNamedCurveP521, true
}
return nil, false
}
// KeyUsage represents the set of actions that are valid for a given key. It's
// a bitmap of the KeyUsage* constants.
type KeyUsage int
const (
KeyUsageDigitalSignature KeyUsage = 1 << iota
KeyUsageContentCommitment
KeyUsageKeyEncipherment
KeyUsageDataEncipherment
KeyUsageKeyAgreement
KeyUsageCertSign
KeyUsageCRLSign
KeyUsageEncipherOnly
KeyUsageDecipherOnly
)
// RFC 5280, 4.2.1.12 Extended Key Usage
//
// anyExtendedKeyUsage OBJECT IDENTIFIER ::= { id-ce-extKeyUsage 0 }
//
// id-kp OBJECT IDENTIFIER ::= { id-pkix 3 }
//
// id-kp-serverAuth OBJECT IDENTIFIER ::= { id-kp 1 }
// id-kp-clientAuth OBJECT IDENTIFIER ::= { id-kp 2 }
// id-kp-codeSigning OBJECT IDENTIFIER ::= { id-kp 3 }
// id-kp-emailProtection OBJECT IDENTIFIER ::= { id-kp 4 }
// id-kp-timeStamping OBJECT IDENTIFIER ::= { id-kp 8 }
// id-kp-OCSPSigning OBJECT IDENTIFIER ::= { id-kp 9 }
var (
oidExtKeyUsageAny = asn1.ObjectIdentifier{2, 5, 29, 37, 0}
oidExtKeyUsageServerAuth = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 1}
oidExtKeyUsageClientAuth = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 2}
oidExtKeyUsageCodeSigning = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 3}
oidExtKeyUsageEmailProtection = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 4}
oidExtKeyUsageIPSECEndSystem = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 5}
oidExtKeyUsageIPSECTunnel = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 6}
oidExtKeyUsageIPSECUser = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 7}
oidExtKeyUsageTimeStamping = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 8}
oidExtKeyUsageOCSPSigning = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 9}
oidExtKeyUsageMicrosoftServerGatedCrypto = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 311, 10, 3, 3}
oidExtKeyUsageNetscapeServerGatedCrypto = asn1.ObjectIdentifier{2, 16, 840, 1, 113730, 4, 1}
)
// ExtKeyUsage represents an extended set of actions that are valid for a given key.
// Each of the ExtKeyUsage* constants define a unique action.
type ExtKeyUsage int
const (
ExtKeyUsageAny ExtKeyUsage = iota
ExtKeyUsageServerAuth
ExtKeyUsageClientAuth
ExtKeyUsageCodeSigning
ExtKeyUsageEmailProtection
ExtKeyUsageIPSECEndSystem
ExtKeyUsageIPSECTunnel
ExtKeyUsageIPSECUser
ExtKeyUsageTimeStamping
ExtKeyUsageOCSPSigning
ExtKeyUsageMicrosoftServerGatedCrypto
ExtKeyUsageNetscapeServerGatedCrypto
)
// extKeyUsageOIDs contains the mapping between an ExtKeyUsage and its OID.
var extKeyUsageOIDs = []struct {
extKeyUsage ExtKeyUsage
oid asn1.ObjectIdentifier
}{
{ExtKeyUsageAny, oidExtKeyUsageAny},
{ExtKeyUsageServerAuth, oidExtKeyUsageServerAuth},
{ExtKeyUsageClientAuth, oidExtKeyUsageClientAuth},
{ExtKeyUsageCodeSigning, oidExtKeyUsageCodeSigning},
{ExtKeyUsageEmailProtection, oidExtKeyUsageEmailProtection},
{ExtKeyUsageIPSECEndSystem, oidExtKeyUsageIPSECEndSystem},
{ExtKeyUsageIPSECTunnel, oidExtKeyUsageIPSECTunnel},
{ExtKeyUsageIPSECUser, oidExtKeyUsageIPSECUser},
{ExtKeyUsageTimeStamping, oidExtKeyUsageTimeStamping},
{ExtKeyUsageOCSPSigning, oidExtKeyUsageOCSPSigning},
{ExtKeyUsageMicrosoftServerGatedCrypto, oidExtKeyUsageMicrosoftServerGatedCrypto},
{ExtKeyUsageNetscapeServerGatedCrypto, oidExtKeyUsageNetscapeServerGatedCrypto},
}
func extKeyUsageFromOID(oid asn1.ObjectIdentifier) (eku ExtKeyUsage, ok bool) {
for _, pair := range extKeyUsageOIDs {
if oid.Equal(pair.oid) {
return pair.extKeyUsage, true
}
}
return
}
func oidFromExtKeyUsage(eku ExtKeyUsage) (oid asn1.ObjectIdentifier, ok bool) {
for _, pair := range extKeyUsageOIDs {
if eku == pair.extKeyUsage {
return pair.oid, true
}
}
return
}
// A Certificate represents an X.509 certificate.
type Certificate struct {
Raw []byte // Complete ASN.1 DER content (certificate, signature algorithm and signature).
RawTBSCertificate []byte // Certificate part of raw ASN.1 DER content.
RawSubjectPublicKeyInfo []byte // DER encoded SubjectPublicKeyInfo.
RawSubject []byte // DER encoded Subject
RawIssuer []byte // DER encoded Issuer
Signature []byte
SignatureAlgorithm SignatureAlgorithm
PublicKeyAlgorithm PublicKeyAlgorithm
PublicKey interface{}
Version int
SerialNumber *big.Int
Issuer pkix.Name
Subject pkix.Name
NotBefore, NotAfter time.Time // Validity bounds.
KeyUsage KeyUsage
// Extensions contains raw X.509 extensions. When parsing certificates,
// this can be used to extract non-critical extensions that are not
// parsed by this package. When marshaling certificates, the Extensions
// field is ignored, see ExtraExtensions.
Extensions []pkix.Extension
// ExtraExtensions contains extensions to be copied, raw, into any
// marshaled certificates. Values override any extensions that would
// otherwise be produced based on the other fields. The ExtraExtensions
// field is not populated when parsing certificates, see Extensions.
ExtraExtensions []pkix.Extension
ExtKeyUsage []ExtKeyUsage // Sequence of extended key usages.
UnknownExtKeyUsage []asn1.ObjectIdentifier // Encountered extended key usages unknown to this package.
BasicConstraintsValid bool // if true then the next two fields are valid.
IsCA bool
MaxPathLen int
SubjectKeyId []byte
AuthorityKeyId []byte
// RFC 5280, 4.2.2.1 (Authority Information Access)
OCSPServer []string
IssuingCertificateURL []string
// Subject Alternate Name values
DNSNames []string
EmailAddresses []string
IPAddresses []net.IP
// Name constraints
PermittedDNSDomainsCritical bool // if true then the name constraints are marked critical.
PermittedDNSDomains []string
// CRL Distribution Points
CRLDistributionPoints []string
PolicyIdentifiers []asn1.ObjectIdentifier
}
// ErrUnsupportedAlgorithm results from attempting to perform an operation that
// involves algorithms that are not currently implemented.
var ErrUnsupportedAlgorithm = errors.New("x509: cannot verify signature: algorithm unimplemented")
// ConstraintViolationError results when a requested usage is not permitted by
// a certificate. For example: checking a signature when the public key isn't a
// certificate signing key.
type ConstraintViolationError struct{}
func (ConstraintViolationError) Error() string {
return "x509: invalid signature: parent certificate cannot sign this kind of certificate"
}
func (c *Certificate) Equal(other *Certificate) bool {
return bytes.Equal(c.Raw, other.Raw)
}
// Entrust have a broken root certificate (CN=Entrust.net Certification
// Authority (2048)) which isn't marked as a CA certificate and is thus invalid
// according to PKIX.
// We recognise this certificate by its SubjectPublicKeyInfo and exempt it
// from the Basic Constraints requirement.
// See http://www.entrust.net/knowledge-base/technote.cfm?tn=7869
//
// TODO(agl): remove this hack once their reissued root is sufficiently
// widespread.
var entrustBrokenSPKI = []byte{
0x30, 0x82, 0x01, 0x22, 0x30, 0x0d, 0x06, 0x09,
0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01,
0x01, 0x05, 0x00, 0x03, 0x82, 0x01, 0x0f, 0x00,
0x30, 0x82, 0x01, 0x0a, 0x02, 0x82, 0x01, 0x01,
0x00, 0x97, 0xa3, 0x2d, 0x3c, 0x9e, 0xde, 0x05,
0xda, 0x13, 0xc2, 0x11, 0x8d, 0x9d, 0x8e, 0xe3,
0x7f, 0xc7, 0x4b, 0x7e, 0x5a, 0x9f, 0xb3, 0xff,
0x62, 0xab, 0x73, 0xc8, 0x28, 0x6b, 0xba, 0x10,
0x64, 0x82, 0x87, 0x13, 0xcd, 0x57, 0x18, 0xff,
0x28, 0xce, 0xc0, 0xe6, 0x0e, 0x06, 0x91, 0x50,
0x29, 0x83, 0xd1, 0xf2, 0xc3, 0x2a, 0xdb, 0xd8,
0xdb, 0x4e, 0x04, 0xcc, 0x00, 0xeb, 0x8b, 0xb6,
0x96, 0xdc, 0xbc, 0xaa, 0xfa, 0x52, 0x77, 0x04,
0xc1, 0xdb, 0x19, 0xe4, 0xae, 0x9c, 0xfd, 0x3c,
0x8b, 0x03, 0xef, 0x4d, 0xbc, 0x1a, 0x03, 0x65,
0xf9, 0xc1, 0xb1, 0x3f, 0x72, 0x86, 0xf2, 0x38,
0xaa, 0x19, 0xae, 0x10, 0x88, 0x78, 0x28, 0xda,
0x75, 0xc3, 0x3d, 0x02, 0x82, 0x02, 0x9c, 0xb9,
0xc1, 0x65, 0x77, 0x76, 0x24, 0x4c, 0x98, 0xf7,
0x6d, 0x31, 0x38, 0xfb, 0xdb, 0xfe, 0xdb, 0x37,
0x02, 0x76, 0xa1, 0x18, 0x97, 0xa6, 0xcc, 0xde,
0x20, 0x09, 0x49, 0x36, 0x24, 0x69, 0x42, 0xf6,
0xe4, 0x37, 0x62, 0xf1, 0x59, 0x6d, 0xa9, 0x3c,
0xed, 0x34, 0x9c, 0xa3, 0x8e, 0xdb, 0xdc, 0x3a,
0xd7, 0xf7, 0x0a, 0x6f, 0xef, 0x2e, 0xd8, 0xd5,
0x93, 0x5a, 0x7a, 0xed, 0x08, 0x49, 0x68, 0xe2,
0x41, 0xe3, 0x5a, 0x90, 0xc1, 0x86, 0x55, 0xfc,
0x51, 0x43, 0x9d, 0xe0, 0xb2, 0xc4, 0x67, 0xb4,
0xcb, 0x32, 0x31, 0x25, 0xf0, 0x54, 0x9f, 0x4b,
0xd1, 0x6f, 0xdb, 0xd4, 0xdd, 0xfc, 0xaf, 0x5e,
0x6c, 0x78, 0x90, 0x95, 0xde, 0xca, 0x3a, 0x48,
0xb9, 0x79, 0x3c, 0x9b, 0x19, 0xd6, 0x75, 0x05,
0xa0, 0xf9, 0x88, 0xd7, 0xc1, 0xe8, 0xa5, 0x09,
0xe4, 0x1a, 0x15, 0xdc, 0x87, 0x23, 0xaa, 0xb2,
0x75, 0x8c, 0x63, 0x25, 0x87, 0xd8, 0xf8, 0x3d,
0xa6, 0xc2, 0xcc, 0x66, 0xff, 0xa5, 0x66, 0x68,
0x55, 0x02, 0x03, 0x01, 0x00, 0x01,
}
// CheckSignatureFrom verifies that the signature on c is a valid signature
// from parent.
func (c *Certificate) CheckSignatureFrom(parent *Certificate) (err error) {
// RFC 5280, 4.2.1.9:
// "If the basic constraints extension is not present in a version 3
// certificate, or the extension is present but the cA boolean is not
// asserted, then the certified public key MUST NOT be used to verify
// certificate signatures."
// (except for Entrust, see comment above entrustBrokenSPKI)
if (parent.Version == 3 && !parent.BasicConstraintsValid ||
parent.BasicConstraintsValid && !parent.IsCA) &&
!bytes.Equal(c.RawSubjectPublicKeyInfo, entrustBrokenSPKI) {
return ConstraintViolationError{}
}
if parent.KeyUsage != 0 && parent.KeyUsage&KeyUsageCertSign == 0 {
return ConstraintViolationError{}
}
if parent.PublicKeyAlgorithm == UnknownPublicKeyAlgorithm {
return ErrUnsupportedAlgorithm
}
// TODO(agl): don't ignore the path length constraint.
return parent.CheckSignature(c.SignatureAlgorithm, c.RawTBSCertificate, c.Signature)
}
// CheckSignature verifies that signature is a valid signature over signed from
// c's public key.
func (c *Certificate) CheckSignature(algo SignatureAlgorithm, signed, signature []byte) (err error) {
var hashType crypto.Hash
switch algo {
case SHA1WithRSA, DSAWithSHA1, ECDSAWithSHA1:
hashType = crypto.SHA1
case SHA256WithRSA, DSAWithSHA256, ECDSAWithSHA256:
hashType = crypto.SHA256
case SHA384WithRSA, ECDSAWithSHA384:
hashType = crypto.SHA384
case SHA512WithRSA, ECDSAWithSHA512:
hashType = crypto.SHA512
default:
return ErrUnsupportedAlgorithm
}
if !hashType.Available() {
return ErrUnsupportedAlgorithm
}
h := hashType.New()
h.Write(signed)
digest := h.Sum(nil)
switch pub := c.PublicKey.(type) {
case *rsa.PublicKey:
return rsa.VerifyPKCS1v15(pub, hashType, digest, signature)
case *dsa.PublicKey:
dsaSig := new(dsaSignature)
if _, err := asn1.Unmarshal(signature, dsaSig); err != nil {
return err
}
if dsaSig.R.Sign() <= 0 || dsaSig.S.Sign() <= 0 {
return errors.New("x509: DSA signature contained zero or negative values")
}
if !dsa.Verify(pub, digest, dsaSig.R, dsaSig.S) {
return errors.New("x509: DSA verification failure")
}
return
case *ecdsa.PublicKey:
ecdsaSig := new(ecdsaSignature)
if _, err := asn1.Unmarshal(signature, ecdsaSig); err != nil {
return err
}
if ecdsaSig.R.Sign() <= 0 || ecdsaSig.S.Sign() <= 0 {
return errors.New("x509: ECDSA signature contained zero or negative values")
}
if !ecdsa.Verify(pub, digest, ecdsaSig.R, ecdsaSig.S) {
return errors.New("x509: ECDSA verification failure")
}
return
}
return ErrUnsupportedAlgorithm
}
// CheckCRLSignature checks that the signature in crl is from c.
func (c *Certificate) CheckCRLSignature(crl *pkix.CertificateList) (err error) {
algo := getSignatureAlgorithmFromOID(crl.SignatureAlgorithm.Algorithm)
return c.CheckSignature(algo, crl.TBSCertList.Raw, crl.SignatureValue.RightAlign())
}
// START CT CHANGES
type UnhandledCriticalExtension struct {
ID asn1.ObjectIdentifier
}
func (h UnhandledCriticalExtension) Error() string {
return fmt.Sprintf("x509: unhandled critical extension (%v)", h.ID)
}
// END CT CHANGES
type basicConstraints struct {
IsCA bool `asn1:"optional"`
MaxPathLen int `asn1:"optional,default:-1"`
}
// RFC 5280 4.2.1.4
type policyInformation struct {
Policy asn1.ObjectIdentifier
// policyQualifiers omitted
}
// RFC 5280, 4.2.1.10
type nameConstraints struct {
Permitted []generalSubtree `asn1:"optional,tag:0"`
Excluded []generalSubtree `asn1:"optional,tag:1"`
}
type generalSubtree struct {
Name string `asn1:"tag:2,optional,ia5"`
}
// RFC 5280, 4.2.2.1
type authorityInfoAccess struct {
Method asn1.ObjectIdentifier
Location asn1.RawValue
}
// RFC 5280, 4.2.1.14
type distributionPoint struct {
DistributionPoint distributionPointName `asn1:"optional,tag:0"`
Reason asn1.BitString `asn1:"optional,tag:1"`
CRLIssuer asn1.RawValue `asn1:"optional,tag:2"`
}
type distributionPointName struct {
FullName asn1.RawValue `asn1:"optional,tag:0"`
RelativeName pkix.RDNSequence `asn1:"optional,tag:1"`
}
func parsePublicKey(algo PublicKeyAlgorithm, keyData *publicKeyInfo) (interface{}, error) {
// START CT CHANGES
var nfe NonFatalErrors
// END CT CHANGES
asn1Data := keyData.PublicKey.RightAlign()
switch algo {
case RSA:
p := new(rsaPublicKey)
_, err := asn1.Unmarshal(asn1Data, p)
if err != nil {
return nil, err
}
if p.N.Sign() <= 0 {
// START CT CHANGES
nfe.AddError(errors.New("x509: RSA modulus is not a positive number"))
// END CT CHANGES
}
if p.E <= 0 {
return nil, errors.New("x509: RSA public exponent is not a positive number")
}
pub := &rsa.PublicKey{
E: p.E,
N: p.N,
}
// START CT CHANGES
if nfe.HasError() {
return pub, nfe
}
// END CT CHANGES
return pub, nil
case DSA:
var p *big.Int
_, err := asn1.Unmarshal(asn1Data, &p)
if err != nil {
return nil, err
}
paramsData := keyData.Algorithm.Parameters.FullBytes
params := new(dsaAlgorithmParameters)
_, err = asn1.Unmarshal(paramsData, params)
if err != nil {
return nil, err
}
if p.Sign() <= 0 || params.P.Sign() <= 0 || params.Q.Sign() <= 0 || params.G.Sign() <= 0 {
return nil, errors.New("x509: zero or negative DSA parameter")
}
pub := &dsa.PublicKey{
Parameters: dsa.Parameters{
P: params.P,
Q: params.Q,
G: params.G,
},
Y: p,
}
return pub, nil
case ECDSA:
paramsData := keyData.Algorithm.Parameters.FullBytes
namedCurveOID := new(asn1.ObjectIdentifier)
_, err := asn1.Unmarshal(paramsData, namedCurveOID)
if err != nil {
return nil, err
}
namedCurve := namedCurveFromOID(*namedCurveOID)
if namedCurve == nil {
return nil, errors.New("x509: unsupported elliptic curve")
}
x, y := elliptic.Unmarshal(namedCurve, asn1Data)
if x == nil {
return nil, errors.New("x509: failed to unmarshal elliptic curve point")
}
pub := &ecdsa.PublicKey{
Curve: namedCurve,
X: x,
Y: y,
}
return pub, nil
default:
return nil, nil
}
}
// START CT CHANGES
// NonFatalErrors is an error type which can hold a number of other errors.
// It's used to collect a range of non-fatal errors which occur while parsing
// a certificate, that way we can still match on certs which technically are
// invalid.
type NonFatalErrors struct {
Errors []error
}
// Adds an error to the list of errors contained by NonFatalErrors.
func (e *NonFatalErrors) AddError(err error) {
e.Errors = append(e.Errors, err)
}
// Attempts to add errors from a second NonFatalErrors to this NonFatalErrors.
// If the passed error is not a NonFatalErrors, return false.
func (e *NonFatalErrors) AddNonFatalErrors(err error) bool {
nfe, isNfe := err.(NonFatalErrors)
if isNfe {
e.Errors = append(e.Errors, nfe.Errors...)
}
return isNfe
}
// Returns a string consisting of the values of Error() from all of the errors
// contained in |e|
func (e NonFatalErrors) Error() string {
r := "NonFatalErrors: "
for _, err := range e.Errors {
r += err.Error() + "; "
}
return r
}
// Returns true if |e| contains at least one error
func (e *NonFatalErrors) HasError() bool {
return len(e.Errors) > 0
}
// END CT CHANGES
func parseCertificate(in *certificate) (*Certificate, error) {
// START CT CHANGES
var nfe NonFatalErrors
// END CT CHANGES
out := new(Certificate)
out.Raw = in.Raw
out.RawTBSCertificate = in.TBSCertificate.Raw
out.RawSubjectPublicKeyInfo = in.TBSCertificate.PublicKey.Raw
out.RawSubject = in.TBSCertificate.Subject.FullBytes
out.RawIssuer = in.TBSCertificate.Issuer.FullBytes
out.Signature = in.SignatureValue.RightAlign()
out.SignatureAlgorithm =
getSignatureAlgorithmFromOID(in.TBSCertificate.SignatureAlgorithm.Algorithm)
out.PublicKeyAlgorithm =
getPublicKeyAlgorithmFromOID(in.TBSCertificate.PublicKey.Algorithm.Algorithm)
var err error
out.PublicKey, err = parsePublicKey(out.PublicKeyAlgorithm, &in.TBSCertificate.PublicKey)
// START CT CHANGES
if err != nil && !nfe.AddNonFatalErrors(err) {
// START CT CHANGES
return nil, err
}
if in.TBSCertificate.SerialNumber.Sign() < 0 {
// START CT CHANGES
nfe.AddError(errors.New("x509: negative serial number"))
// END CT CHANGES
}
out.Version = in.TBSCertificate.Version + 1
out.SerialNumber = in.TBSCertificate.SerialNumber
var issuer, subject pkix.RDNSequence
if _, err := asn1.Unmarshal(in.TBSCertificate.Subject.FullBytes, &subject); err != nil {
return nil, err
}
if _, err := asn1.Unmarshal(in.TBSCertificate.Issuer.FullBytes, &issuer); err != nil {
return nil, err
}
out.Issuer.FillFromRDNSequence(&issuer)
out.Subject.FillFromRDNSequence(&subject)
out.NotBefore = in.TBSCertificate.Validity.NotBefore
out.NotAfter = in.TBSCertificate.Validity.NotAfter
for _, e := range in.TBSCertificate.Extensions {
out.Extensions = append(out.Extensions, e)
if len(e.Id) == 4 && e.Id[0] == 2 && e.Id[1] == 5 && e.Id[2] == 29 {
switch e.Id[3] {
case 15:
// RFC 5280, 4.2.1.3
var usageBits asn1.BitString
_, err := asn1.Unmarshal(e.Value, &usageBits)
if err == nil {
var usage int
for i := 0; i < 9; i++ {
if usageBits.At(i) != 0 {
usage |= 1 << uint(i)
}
}
out.KeyUsage = KeyUsage(usage)
continue
}
case 19:
// RFC 5280, 4.2.1.9
var constraints basicConstraints
_, err := asn1.Unmarshal(e.Value, &constraints)
if err == nil {
out.BasicConstraintsValid = true
out.IsCA = constraints.IsCA
out.MaxPathLen = constraints.MaxPathLen
continue
}
case 17:
// RFC 5280, 4.2.1.6
// SubjectAltName ::= GeneralNames
//
// GeneralNames ::= SEQUENCE SIZE (1..MAX) OF GeneralName
//
// GeneralName ::= CHOICE {
// otherName [0] OtherName,
// rfc822Name [1] IA5String,
// dNSName [2] IA5String,
// x400Address [3] ORAddress,
// directoryName [4] Name,
// ediPartyName [5] EDIPartyName,
// uniformResourceIdentifier [6] IA5String,
// iPAddress [7] OCTET STRING,
// registeredID [8] OBJECT IDENTIFIER }
var seq asn1.RawValue
_, err := asn1.Unmarshal(e.Value, &seq)
if err != nil {
return nil, err
}
if !seq.IsCompound || seq.Tag != 16 || seq.Class != 0 {
return nil, asn1.StructuralError{Msg: "bad SAN sequence"}
}
parsedName := false
rest := seq.Bytes
for len(rest) > 0 {
var v asn1.RawValue
rest, err = asn1.Unmarshal(rest, &v)
if err != nil {
return nil, err
}
switch v.Tag {
case 1:
out.EmailAddresses = append(out.EmailAddresses, string(v.Bytes))
parsedName = true
case 2:
out.DNSNames = append(out.DNSNames, string(v.Bytes))
parsedName = true
case 7:
switch len(v.Bytes) {
case net.IPv4len, net.IPv6len:
out.IPAddresses = append(out.IPAddresses, v.Bytes)
default:
// START CT CHANGES
nfe.AddError(fmt.Errorf("x509: certificate contained IP address of length %d : %v", len(v.Bytes), v.Bytes))
// END CT CHANGES
}
}
}
if parsedName {
continue
}
// If we didn't parse any of the names then we
// fall through to the critical check below.
case 30:
// RFC 5280, 4.2.1.10
// NameConstraints ::= SEQUENCE {
// permittedSubtrees [0] GeneralSubtrees OPTIONAL,
// excludedSubtrees [1] GeneralSubtrees OPTIONAL }
//
// GeneralSubtrees ::= SEQUENCE SIZE (1..MAX) OF GeneralSubtree
//
// GeneralSubtree ::= SEQUENCE {
// base GeneralName,
// minimum [0] BaseDistance DEFAULT 0,
// maximum [1] BaseDistance OPTIONAL }
//
// BaseDistance ::= INTEGER (0..MAX)
var constraints nameConstraints
_, err := asn1.Unmarshal(e.Value, &constraints)
if err != nil {
return nil, err
}
if len(constraints.Excluded) > 0 && e.Critical {
// START CT CHANGES
nfe.AddError(UnhandledCriticalExtension{e.Id})
// END CT CHANGES
}
for _, subtree := range constraints.Permitted {
if len(subtree.Name) == 0 {
if e.Critical {
// START CT CHANGES
nfe.AddError(UnhandledCriticalExtension{e.Id})
// END CT CHANGES
}
continue
}
out.PermittedDNSDomains = append(out.PermittedDNSDomains, subtree.Name)
}
continue
case 31:
// RFC 5280, 4.2.1.14
// CRLDistributionPoints ::= SEQUENCE SIZE (1..MAX) OF DistributionPoint
//
// DistributionPoint ::= SEQUENCE {
// distributionPoint [0] DistributionPointName OPTIONAL,
// reasons [1] ReasonFlags OPTIONAL,
// cRLIssuer [2] GeneralNames OPTIONAL }
//
// DistributionPointName ::= CHOICE {
// fullName [0] GeneralNames,
// nameRelativeToCRLIssuer [1] RelativeDistinguishedName }
var cdp []distributionPoint
_, err := asn1.Unmarshal(e.Value, &cdp)
if err != nil {
return nil, err
}
for _, dp := range cdp {
var n asn1.RawValue
_, err = asn1.Unmarshal(dp.DistributionPoint.FullName.Bytes, &n)
if err != nil {
return nil, err
}
if n.Tag == 6 {
out.CRLDistributionPoints = append(out.CRLDistributionPoints, string(n.Bytes))
}
}
continue
case 35:
// RFC 5280, 4.2.1.1
var a authKeyId
_, err = asn1.Unmarshal(e.Value, &a)
if err != nil {
return nil, err
}
out.AuthorityKeyId = a.Id
continue
case 37:
// RFC 5280, 4.2.1.12. Extended Key Usage
// id-ce-extKeyUsage OBJECT IDENTIFIER ::= { id-ce 37 }
//
// ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId
//
// KeyPurposeId ::= OBJECT IDENTIFIER
var keyUsage []asn1.ObjectIdentifier
_, err = asn1.Unmarshal(e.Value, &keyUsage)
if err != nil {
return nil, err
}
for _, u := range keyUsage {
if extKeyUsage, ok := extKeyUsageFromOID(u); ok {
out.ExtKeyUsage = append(out.ExtKeyUsage, extKeyUsage)
} else {
out.UnknownExtKeyUsage = append(out.UnknownExtKeyUsage, u)
}
}
continue
case 14:
// RFC 5280, 4.2.1.2
var keyid []byte
_, err = asn1.Unmarshal(e.Value, &keyid)
if err != nil {
return nil, err
}
out.SubjectKeyId = keyid
continue
case 32:
// RFC 5280 4.2.1.4: Certificate Policies
var policies []policyInformation
if _, err = asn1.Unmarshal(e.Value, &policies); err != nil {
return nil, err
}
out.PolicyIdentifiers = make([]asn1.ObjectIdentifier, len(policies))
for i, policy := range policies {
out.PolicyIdentifiers[i] = policy.Policy
}
}
} else if e.Id.Equal(oidExtensionAuthorityInfoAccess) {
// RFC 5280 4.2.2.1: Authority Information Access
var aia []authorityInfoAccess
if _, err = asn1.Unmarshal(e.Value, &aia); err != nil {
return nil, err
}
for _, v := range aia {
// GeneralName: uniformResourceIdentifier [6] IA5String
if v.Location.Tag != 6 {
continue
}
if v.Method.Equal(oidAuthorityInfoAccessOcsp) {
out.OCSPServer = append(out.OCSPServer, string(v.Location.Bytes))
} else if v.Method.Equal(oidAuthorityInfoAccessIssuers) {
out.IssuingCertificateURL = append(out.IssuingCertificateURL, string(v.Location.Bytes))
}
}
}
if e.Critical {
// START CT CHANGES
nfe.AddError(UnhandledCriticalExtension{e.Id})
// END CT CHANGES
}
}
// START CT CHANGES
if nfe.HasError() {
return out, nfe
}
// END CT CHANGES
return out, nil
}
// START CT CHANGES
// ParseTBSCertificate parses a single TBSCertificate from the given ASN.1 DER data.
// The parsed data is returned in a Certificate struct for ease of access.
func ParseTBSCertificate(asn1Data []byte) (*Certificate, error) {
var tbsCert tbsCertificate
rest, err := asn1.Unmarshal(asn1Data, &tbsCert)
if err != nil {
return nil, err
}
if len(rest) > 0 {
return nil, asn1.SyntaxError{Msg: "trailing data"}
}
return parseCertificate(&certificate{
Raw: tbsCert.Raw,
TBSCertificate: tbsCert})
}
// END CT CHANGES
// ParseCertificate parses a single certificate from the given ASN.1 DER data.
func ParseCertificate(asn1Data []byte) (*Certificate, error) {
var cert certificate
rest, err := asn1.Unmarshal(asn1Data, &cert)
if err != nil {
return nil, err
}
if len(rest) > 0 {
return nil, asn1.SyntaxError{Msg: "trailing data"}
}
return parseCertificate(&cert)
}
// ParseCertificates parses one or more certificates from the given ASN.1 DER
// data. The certificates must be concatenated with no intermediate padding.
func ParseCertificates(asn1Data []byte) ([]*Certificate, error) {
var v []*certificate
for len(asn1Data) > 0 {
cert := new(certificate)
var err error
asn1Data, err = asn1.Unmarshal(asn1Data, cert)
if err != nil {
return nil, err
}
v = append(v, cert)
}
ret := make([]*Certificate, len(v))
for i, ci := range v {
cert, err := parseCertificate(ci)
if err != nil {
return nil, err
}
ret[i] = cert
}
return ret, nil
}
func reverseBitsInAByte(in byte) byte {
b1 := in>>4 | in<<4
b2 := b1>>2&0x33 | b1<<2&0xcc
b3 := b2>>1&0x55 | b2<<1&0xaa
return b3
}
var (
oidExtensionSubjectKeyId = []int{2, 5, 29, 14}
oidExtensionKeyUsage = []int{2, 5, 29, 15}
oidExtensionExtendedKeyUsage = []int{2, 5, 29, 37}
oidExtensionAuthorityKeyId = []int{2, 5, 29, 35}
oidExtensionBasicConstraints = []int{2, 5, 29, 19}
oidExtensionSubjectAltName = []int{2, 5, 29, 17}
oidExtensionCertificatePolicies = []int{2, 5, 29, 32}
oidExtensionNameConstraints = []int{2, 5, 29, 30}
oidExtensionCRLDistributionPoints = []int{2, 5, 29, 31}
oidExtensionAuthorityInfoAccess = []int{1, 3, 6, 1, 5, 5, 7, 1, 1}
)
var (
oidAuthorityInfoAccessOcsp = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 48, 1}
oidAuthorityInfoAccessIssuers = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 48, 2}
)
// oidNotInExtensions returns whether an extension with the given oid exists in
// extensions.
func oidInExtensions(oid asn1.ObjectIdentifier, extensions []pkix.Extension) bool {
for _, e := range extensions {
if e.Id.Equal(oid) {
return true
}
}
return false
}
func buildExtensions(template *Certificate) (ret []pkix.Extension, err error) {
ret = make([]pkix.Extension, 10 /* maximum number of elements. */)
n := 0
if template.KeyUsage != 0 &&
!oidInExtensions(oidExtensionKeyUsage, template.ExtraExtensions) {
ret[n].Id = oidExtensionKeyUsage
ret[n].Critical = true
var a [2]byte
a[0] = reverseBitsInAByte(byte(template.KeyUsage))
a[1] = reverseBitsInAByte(byte(template.KeyUsage >> 8))
l := 1
if a[1] != 0 {
l = 2
}
ret[n].Value, err = asn1.Marshal(asn1.BitString{Bytes: a[0:l], BitLength: l * 8})
if err != nil {
return
}
n++
}
if (len(template.ExtKeyUsage) > 0 || len(template.UnknownExtKeyUsage) > 0) &&
!oidInExtensions(oidExtensionExtendedKeyUsage, template.ExtraExtensions) {
ret[n].Id = oidExtensionExtendedKeyUsage
var oids []asn1.ObjectIdentifier
for _, u := range template.ExtKeyUsage {
if oid, ok := oidFromExtKeyUsage(u); ok {
oids = append(oids, oid)
} else {
panic("internal error")
}
}
oids = append(oids, template.UnknownExtKeyUsage...)
ret[n].Value, err = asn1.Marshal(oids)
if err != nil {
return
}
n++
}
if template.BasicConstraintsValid && !oidInExtensions(oidExtensionBasicConstraints, template.ExtraExtensions) {
ret[n].Id = oidExtensionBasicConstraints
ret[n].Value, err = asn1.Marshal(basicConstraints{template.IsCA, template.MaxPathLen})
ret[n].Critical = true
if err != nil {
return
}
n++
}
if len(template.SubjectKeyId) > 0 && !oidInExtensions(oidExtensionSubjectKeyId, template.ExtraExtensions) {
ret[n].Id = oidExtensionSubjectKeyId
ret[n].Value, err = asn1.Marshal(template.SubjectKeyId)
if err != nil {
return
}
n++
}
if len(template.AuthorityKeyId) > 0 && !oidInExtensions(oidExtensionAuthorityKeyId, template.ExtraExtensions) {
ret[n].Id = oidExtensionAuthorityKeyId
ret[n].Value, err = asn1.Marshal(authKeyId{template.AuthorityKeyId})
if err != nil {
return
}
n++
}
if (len(template.OCSPServer) > 0 || len(template.IssuingCertificateURL) > 0) &&
!oidInExtensions(oidExtensionAuthorityInfoAccess, template.ExtraExtensions) {
ret[n].Id = oidExtensionAuthorityInfoAccess
var aiaValues []authorityInfoAccess
for _, name := range template.OCSPServer {
aiaValues = append(aiaValues, authorityInfoAccess{
Method: oidAuthorityInfoAccessOcsp,
Location: asn1.RawValue{Tag: 6, Class: 2, Bytes: []byte(name)},
})
}
for _, name := range template.IssuingCertificateURL {
aiaValues = append(aiaValues, authorityInfoAccess{
Method: oidAuthorityInfoAccessIssuers,
Location: asn1.RawValue{Tag: 6, Class: 2, Bytes: []byte(name)},
})
}
ret[n].Value, err = asn1.Marshal(aiaValues)
if err != nil {
return
}
n++
}
if (len(template.DNSNames) > 0 || len(template.EmailAddresses) > 0 || len(template.IPAddresses) > 0) &&
!oidInExtensions(oidExtensionSubjectAltName, template.ExtraExtensions) {
ret[n].Id = oidExtensionSubjectAltName
var rawValues []asn1.RawValue
for _, name := range template.DNSNames {
rawValues = append(rawValues, asn1.RawValue{Tag: 2, Class: 2, Bytes: []byte(name)})
}
for _, email := range template.EmailAddresses {
rawValues = append(rawValues, asn1.RawValue{Tag: 1, Class: 2, Bytes: []byte(email)})
}
for _, rawIP := range template.IPAddresses {
// If possible, we always want to encode IPv4 addresses in 4 bytes.
ip := rawIP.To4()
if ip == nil {
ip = rawIP
}
rawValues = append(rawValues, asn1.RawValue{Tag: 7, Class: 2, Bytes: ip})
}
ret[n].Value, err = asn1.Marshal(rawValues)
if err != nil {
return
}
n++
}
if len(template.PolicyIdentifiers) > 0 &&
!oidInExtensions(oidExtensionCertificatePolicies, template.ExtraExtensions) {
ret[n].Id = oidExtensionCertificatePolicies
policies := make([]policyInformation, len(template.PolicyIdentifiers))
for i, policy := range template.PolicyIdentifiers {
policies[i].Policy = policy
}
ret[n].Value, err = asn1.Marshal(policies)
if err != nil {
return
}
n++
}
if len(template.PermittedDNSDomains) > 0 &&
!oidInExtensions(oidExtensionNameConstraints, template.ExtraExtensions) {
ret[n].Id = oidExtensionNameConstraints
ret[n].Critical = template.PermittedDNSDomainsCritical
var out nameConstraints
out.Permitted = make([]generalSubtree, len(template.PermittedDNSDomains))
for i, permitted := range template.PermittedDNSDomains {
out.Permitted[i] = generalSubtree{Name: permitted}
}
ret[n].Value, err = asn1.Marshal(out)
if err != nil {
return
}
n++
}
if len(template.CRLDistributionPoints) > 0 &&
!oidInExtensions(oidExtensionCRLDistributionPoints, template.ExtraExtensions) {
ret[n].Id = oidExtensionCRLDistributionPoints
var crlDp []distributionPoint
for _, name := range template.CRLDistributionPoints {
rawFullName, _ := asn1.Marshal(asn1.RawValue{Tag: 6, Class: 2, Bytes: []byte(name)})
dp := distributionPoint{
DistributionPoint: distributionPointName{
FullName: asn1.RawValue{Tag: 0, Class: 2, Bytes: rawFullName},
},
}
crlDp = append(crlDp, dp)
}
ret[n].Value, err = asn1.Marshal(crlDp)
if err != nil {
return
}
n++
}
// Adding another extension here? Remember to update the maximum number
// of elements in the make() at the top of the function.
return append(ret[:n], template.ExtraExtensions...), nil
}
func subjectBytes(cert *Certificate) ([]byte, error) {
if len(cert.RawSubject) > 0 {
return cert.RawSubject, nil
}
return asn1.Marshal(cert.Subject.ToRDNSequence())
}
// CreateCertificate creates a new certificate based on a template. The
// following members of template are used: SerialNumber, Subject, NotBefore,
// NotAfter, KeyUsage, ExtKeyUsage, UnknownExtKeyUsage, BasicConstraintsValid,
// IsCA, MaxPathLen, SubjectKeyId, DNSNames, PermittedDNSDomainsCritical,
// PermittedDNSDomains.
//
// The certificate is signed by parent. If parent is equal to template then the
// certificate is self-signed. The parameter pub is the public key of the
// signee and priv is the private key of the signer.
//
// The returned slice is the certificate in DER encoding.
//
// The only supported key types are RSA and ECDSA (*rsa.PublicKey or
// *ecdsa.PublicKey for pub, *rsa.PrivateKey or *ecdsa.PublicKey for priv).
func CreateCertificate(rand io.Reader, template, parent *Certificate, pub interface{}, priv interface{}) (cert []byte, err error) {
var publicKeyBytes []byte
var publicKeyAlgorithm pkix.AlgorithmIdentifier
if publicKeyBytes, publicKeyAlgorithm, err = marshalPublicKey(pub); err != nil {
return nil, err
}
var signatureAlgorithm pkix.AlgorithmIdentifier
var hashFunc crypto.Hash
switch priv := priv.(type) {
case *rsa.PrivateKey:
signatureAlgorithm.Algorithm = oidSignatureSHA1WithRSA
hashFunc = crypto.SHA1
case *ecdsa.PrivateKey:
switch priv.Curve {
case elliptic.P224(), elliptic.P256():
hashFunc = crypto.SHA256
signatureAlgorithm.Algorithm = oidSignatureECDSAWithSHA256
case elliptic.P384():
hashFunc = crypto.SHA384
signatureAlgorithm.Algorithm = oidSignatureECDSAWithSHA384
case elliptic.P521():
hashFunc = crypto.SHA512
signatureAlgorithm.Algorithm = oidSignatureECDSAWithSHA512
default:
return nil, errors.New("x509: unknown elliptic curve")
}
default:
return nil, errors.New("x509: only RSA and ECDSA private keys supported")
}
if err != nil {
return
}
if len(parent.SubjectKeyId) > 0 {
template.AuthorityKeyId = parent.SubjectKeyId
}
extensions, err := buildExtensions(template)
if err != nil {
return
}
asn1Issuer, err := subjectBytes(parent)
if err != nil {
return
}
asn1Subject, err := subjectBytes(template)
if err != nil {
return
}
encodedPublicKey := asn1.BitString{BitLength: len(publicKeyBytes) * 8, Bytes: publicKeyBytes}
c := tbsCertificate{
Version: 2,
SerialNumber: template.SerialNumber,
SignatureAlgorithm: signatureAlgorithm,
Issuer: asn1.RawValue{FullBytes: asn1Issuer},
Validity: validity{template.NotBefore.UTC(), template.NotAfter.UTC()},
Subject: asn1.RawValue{FullBytes: asn1Subject},
PublicKey: publicKeyInfo{nil, publicKeyAlgorithm, encodedPublicKey},
Extensions: extensions,
}
tbsCertContents, err := asn1.Marshal(c)
if err != nil {
return
}
c.Raw = tbsCertContents
h := hashFunc.New()
h.Write(tbsCertContents)
digest := h.Sum(nil)
var signature []byte
switch priv := priv.(type) {
case *rsa.PrivateKey:
signature, err = rsa.SignPKCS1v15(rand, priv, hashFunc, digest)
case *ecdsa.PrivateKey:
var r, s *big.Int
if r, s, err = ecdsa.Sign(rand, priv, digest); err == nil {
signature, err = asn1.Marshal(ecdsaSignature{r, s})
}
default:
panic("internal error")
}
if err != nil {
return
}
cert, err = asn1.Marshal(certificate{
nil,
c,
signatureAlgorithm,
asn1.BitString{Bytes: signature, BitLength: len(signature) * 8},
})
return
}
// pemCRLPrefix is the magic string that indicates that we have a PEM encoded
// CRL.
var pemCRLPrefix = []byte("-----BEGIN X509 CRL")
// pemType is the type of a PEM encoded CRL.
var pemType = "X509 CRL"
// ParseCRL parses a CRL from the given bytes. It's often the case that PEM
// encoded CRLs will appear where they should be DER encoded, so this function
// will transparently handle PEM encoding as long as there isn't any leading
// garbage.
func ParseCRL(crlBytes []byte) (certList *pkix.CertificateList, err error) {
if bytes.HasPrefix(crlBytes, pemCRLPrefix) {
block, _ := pem.Decode(crlBytes)
if block != nil && block.Type == pemType {
crlBytes = block.Bytes
}
}
return ParseDERCRL(crlBytes)
}
// ParseDERCRL parses a DER encoded CRL from the given bytes.
func ParseDERCRL(derBytes []byte) (certList *pkix.CertificateList, err error) {
certList = new(pkix.CertificateList)
_, err = asn1.Unmarshal(derBytes, certList)
if err != nil {
certList = nil
}
return
}
// CreateCRL returns a DER encoded CRL, signed by this Certificate, that
// contains the given list of revoked certificates.
//
// The only supported key type is RSA (*rsa.PrivateKey for priv).
func (c *Certificate) CreateCRL(rand io.Reader, priv interface{}, revokedCerts []pkix.RevokedCertificate, now, expiry time.Time) (crlBytes []byte, err error) {
rsaPriv, ok := priv.(*rsa.PrivateKey)
if !ok {
return nil, errors.New("x509: non-RSA private keys not supported")
}
tbsCertList := pkix.TBSCertificateList{
Version: 2,
Signature: pkix.AlgorithmIdentifier{
Algorithm: oidSignatureSHA1WithRSA,
},
Issuer: c.Subject.ToRDNSequence(),
ThisUpdate: now.UTC(),
NextUpdate: expiry.UTC(),
RevokedCertificates: revokedCerts,
}
tbsCertListContents, err := asn1.Marshal(tbsCertList)
if err != nil {
return
}
h := sha1.New()
h.Write(tbsCertListContents)
digest := h.Sum(nil)
signature, err := rsa.SignPKCS1v15(rand, rsaPriv, crypto.SHA1, digest)
if err != nil {
return
}
return asn1.Marshal(pkix.CertificateList{
TBSCertList: tbsCertList,
SignatureAlgorithm: pkix.AlgorithmIdentifier{
Algorithm: oidSignatureSHA1WithRSA,
},
SignatureValue: asn1.BitString{Bytes: signature, BitLength: len(signature) * 8},
})
}
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